APPLICATION OF WEIBULL THEORY TO RANDOM-FIBER COMPOSITES

The ultimate tensile strain in complex stress states such as biaxial b ending can be significantly higher than the ultimate strain measured b y tensile rests. By the use of models that account for this effect, op timal design solutions are facilitated and weight and money can be sav ed. In this work, Weibull theory has been used to develop a model to d escribe tensile failure for non-uniform biaxial loading of random-fibr e composite laminates. The basis for the model is the observation that fibre bundles dominate the failure behaviour in tension, and an assum ption that fibre-bundle failure can be described by the Weibull theory . The material data needed for strength predictions can be determined by tensile tests. Strength predictions and test data have been compare d for tension, three- and four-point bending and biaxial bending for a continuous-glass-mat/vinyl-ester composite.